应用非工频暂态分量的配电网故障选线方法

Faulty line selection with non-power frequency transient components of distribution network

在Matlab/Simulink环境下对小电流接地系统配电网模型进行大量仿真分析,根据小电流接地系统单相接地故障初期具有明显暂态分量的特点,应用希尔伯特-黄变换HHT(Hilbert-Huang Transform)计算出各条出线在单相故障初期各时刻零序电流所含的各种暂态频率分量成分,根据分解结果剔出工频稳态分量从而得到故障特征明显的非工频暂态单相故障特征分量。总结分解变换结果发现:故障后1/10周期时间内故障线路的非工频分量与非故障线路非工频分量极性相反,故障线路非工频量幅值明显大于非故障线路的故障特征。基于此提出一种应用非工频暂态分量的配电网故障选线方法,选线结果表明该方法应用于小电流单相接地故障选线准确可靠。

A neutral non-effectual grounding distribution network model is established with Matlab/Simulink and simulated for many cases.As the non-effectively grounding distribution system has distinct transient components at the beginning of single-phase-to-earth fault,HHT（Hilbert-Huang Transform） is applied to calcu-late the transient frequency components of zero-sequence current,from which the non-power frequency transient components are extracted to detect the single-phase-to-earth fault.Simulative results suggest that,the polarity of non-power frequency component of faulty line is contrary to that of healthy line and the amplitude of non-power frequency of faulty line is much larger than that of healthy line within the one tenth of period after fault.It is proposed to apply the non-power frequency transient components in the faulty line selection for the single-phase-to-earth fault of distribution network.Results indicate it is precise and reliable.